The present invention is directed to a tunable laser diode based on a TTG laser diode.
Electronically tunable laser diodes having an extremely great tuning range are required in modern optical communications technology (for example, wavelength - division multiplex systems), in metrology (for example, in range-finding) and in sensor analysis (for example, air analysis with infrared spectroscopy). A tunable laser diode having an active layer and tuning layer arranged transversely relative to one another is disclosed in European Patent Application EP 0 360 011 (TTG laser). In the prior art, it was predominately hybrid designs composed of a laser diode and an external resonator with mechanical wavelength setting that were used for an especially broad tuning range. For example, the ACA laser or the Y laser are monolithically integrated designs. In the ACA laser (see ECOC'91/IOOC'91, pages 21-24), the principle of forward coupling is utilized for enlarging the tuning range. The longitudinal sectioning into three zones represents a disadvantage of the ACA laser, this making manufacture of the component more difficult and increasing the laser length. The Y laser (see M. Schilling et al., "Widely Tunable Y-Coupled Cavity Integrated Interferometric Injection Laser" in Electron. Lett. 26, 243-244 (1990 )) has the critical disadvantage of an extremely complicated drive due to four control currents, whereby the control functions of light power and wavelength are not completely separated but are simultaneously influenced by all four control currents.